Temperature independent current-control, in particular, a temperature independent current limitation, in integrated circuits may be a formidable task when standard solutions are inappropriate for being too expensive (such as, e.g., concepts using band-gap references because such circuits entail too many components in order to be integrated within a given chip area or at given costs) or too inaccurate (such as, e.g., concepts employing so-called sense-FETs for providing a current sense signal).
Metal shunt resistors are commonly used in integrated power semiconductor components. When connected in series to the load path of the power semiconductor component the voltage drop across the shunt may be used as a current sense signal and further processed, for example, in a current control circuit (current limiter, current regulator, etc.).
However, metal shunt resistors typically have a significant (positive) temperature coefficient. Pure metals typically exhibit temperature coefficients of 0.4 percent per Kelvin. Thus, metal shunts can not be used when a precise measurement is required within a large temperature range without considering the temperature dependent change of resistance. For this reason alloys have been developed that exhibit a temperature coefficient close to zero. However such alloys can not processed in integrated circuits where mainly pure metals such as aluminum, copper and gold are processed to form metallization layers.
There is a general need for a precise current control, in particular, a precise current limitation, in integrated circuits. The required current measurement components and circuitry should be producible with well-established semiconductor production processes.